Method Of Selecting And Broadcasting Over A Transmission Frequency And Device For The Same

ABSTRACT

In some embodiments, a method of identifying at least one transmission frequency in a set of carrier frequencies can include: (a) determining a first signal strength for each carrier frequency in the set of carrier frequencies; (b) choosing a first transmission frequency from the set of carrier frequencies at least partially based on the first signal strength of each of the carrier frequencies of the set of carrier frequencies; and (c) broadcasting electrical signals over the first transmission frequency. Other embodiments are disclosed herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims is a continuation of U.S. patent applicationSer. No. 12/171,202, filed Jul. 10, 2008, which claim priority to U.S.Provisional Patent Application No. 60/959,092, filed Jul. 10, 2007. U.S.patent application Ser. No. 12/171,202 and U.S. Provisional PatentApplication No. 60/959,092 are incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to methods and devices for transmittingelectrical signals, and relates more particularly to methods, devices,and systems for selecting a transmission frequency, and broadcasting theelectrical signals over the transmission frequency or other frequencies.

DESCRIPTION OF THE BACKGROUND

With the increasing popularity of portable media players, people want tolisten to music or other media stored in their portable media playerswhile driving in their vehicles. In particular, people want to use theirvehicle's radio and speaker system to listen to the music and othermedia stored in their portable media players. Most radios in vehicles,however, do not easily couple to portable media players. Instead, somevehicles have input connectors or cassette players to which the portablemedia players can be coupled.

In vehicles that do not have input connectors or cassette players,people have to find other ways of sending the audio signals from theirportable media players to the vehicles' radio or speaker system. Onecommon method involves coupling a portable media player to atransmitter, which wirelessly transmits the audio signals to thevehicle's radio over a carrier frequency.

While using a transmitter solves the problem of coupling the portablemedia player to the vehicle's radio and speaker system, it creates newproblems and hazards for the driver of the vehicle. For example, adriver must find an unused carrier frequency over which to transmit theaudio signals. Finding the unused frequency can be difficult anddistracting to the driver. Because the vehicle is moving, the unusedcarrier frequencies are constantly changing as the vehicle moves in andout of range of different radio stations. Furthermore, tall buildings,hills, and any other large structures can temporarily block electricalsignals on a carrier frequency and make a used carrier frequency seemempty for a short period of time. These factors can make finding anunused carrier frequency frustrating and potentially dangerous if adriver becomes distracted while trying to find an unused carrierfrequency.

Accordingly, a need exists for an electrical device, system, and methodthat allows a person to easily find unused carrier frequencies fortransmitting audio or other electrical signals.

BRIEF DESCRIPTION OF THE DRAWINGS

To facilitate further description of the embodiments, the followingdrawings are provided in which:

FIG. 1 is a block diagram illustrating an example of an electricaldevice configured to receive electrical signals from at least one sourceand to transmit the electrical signals to at least one receiving device,according to a first embodiment;

FIG. 2 is a flow chart illustrating an example of a method ofidentifying at least one transmission frequency from a set of carrierfrequencies to use with the electrical device of FIG. 1, according tothe first embodiment;

FIG. 3 is a flow chart illustrating an example of an activity ofidentifying one or more unused carrier frequencies in the set of carrierfrequencies, according to the first embodiment;

FIG. 4 is a flow chart illustrating an example of a procedure ofscanning the set of carrier frequencies, according to the firstembodiment;

FIG. 5 is a flow chart illustrating an example of an activity ofdetermining an empty carrier frequency, according to the firstembodiment;

FIG. 6 is a flow chart illustrating an example of an activity of rankingthe empty carrier frequencies, according to the first embodiment;

FIG. 7 is a flow chart illustrating an example of an activity ofobtaining a transmission frequency for a user, according to the firstembodiment;

FIG. 8 is a flow chart illustrating an example of a procedure ofproviding the transmission frequency to a user, according to anembodiment;

FIG. 9 is a front perspective representational view illustrating anexample of the electrical device of FIG. 1 coupled to the source of FIG.1, according to the first embodiment;

FIG. 10 is a block diagram illustrating an example of the coupling of areceiver of the electrical device of FIG. 1 to an external antenna,according to the first embodiment; and

FIG. 11 is a circuit diagram illustrating an example of an externalantenna matching circuit and other circuits in the electrical device ofFIG. 1, according to the first embodiment.

For simplicity and clarity of illustration, the drawing figuresillustrate the general manner of construction, and descriptions anddetails of well-known features and techniques may be omitted to avoidunnecessarily obscuring the invention. Additionally, elements in thedrawing figures are not necessarily drawn to scale. For example, thedimensions of some of the elements in the figures may be exaggeratedrelative to other elements to help improve understanding of embodimentsof the present invention. The same reference numerals in differentfigures denote the same elements.

The terms “first,” “second,” “third,” “fourth,” and the like in thedescription and in the claims, if any, are used for distinguishingbetween similar elements and not necessarily for describing a particularsequential or chronological order. It is to be understood that the termsso used are interchangeable under appropriate circumstances such thatthe embodiments of the invention described herein are, for example,capable of operation in sequences other than those illustrated orotherwise described herein. Furthermore, the terms “include,” and“have,” and any variations thereof, are intended to cover anon-exclusive inclusion, such that a process, method, system, article,or apparatus that comprises a list of elements is not necessarilylimited to those elements, but may include other elements not expresslylisted or inherent to such process, method, article, or apparatus.

The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,”“under,” and the like in the description and in the claims, if any, areused for descriptive purposes and not necessarily for describingpermanent relative positions. It is to be understood that the terms soused are interchangeable under appropriate circumstances such that theembodiments of the invention described herein are, for example, capableof operation in other orientations than those illustrated or otherwisedescribed herein.

The terms “couple,” “coupled,” “couples,” “coupling,” and the likeshould be broadly understood and refer to connecting two or moreelements or signals, electrically and/or mechanically, either directlyor indirectly through intervening circuitry and/or elements. Two or moreelectrical elements may be electrically coupled, either direct orindirectly, but not be mechanically coupled; two or more mechanicalelements may be mechanically coupled, either direct or indirectly, butnot be electrically coupled; two or more electrical elements may bemechanically coupled, directly or indirectly, but not be electricallycoupled. Coupling (whether only mechanical, only electrical, or both)may be for any length of time, e.g., permanent or semi-permanent or onlyfor an instant.

“Electrical coupling” and the like should be broadly understood andinclude coupling involving any electrical signal, whether a powersignal, a data signal, and/or other types or combinations of electricalsignals. “Mechanical coupling” and the like should be broadly understoodand include mechanical coupling of all types.

The absence of the word “removably,” “removable,” and the like near theword “coupled,” and the like does not mean that the coupling, etc. inquestion is or is not removable.

As used herein, “vehicle” and the like should be broadly understood andrefer to vehicles of all types and designs, including watercraft,aircraft (both lighter-than-air and heavier-than-air), automobiles,trucks, carriages, golf carts, motorcycles, etc.

DETAILED DESCRIPTION OF EXAMPLES OF EMBODIMENTS

In a number of embodiments, a method of identifying at least onetransmission frequency in a set of carrier frequencies can include: (a)determining a first signal strength for each carrier frequency in theset of carrier frequencies; (b) choosing a first transmission frequencyfrom the set of carrier frequencies at least partially based on thefirst signal strength of each of the carrier frequencies of the set ofcarrier frequencies; and (c) broadcasting electrical signals over thefirst transmission frequency.

In the same or different embodiments, a method of selecting one or moretransmission frequencies from two more carrier frequencies can include:(a) identifying one or more first unused carrier frequencies from thetwo or more carrier frequencies; (b) determining first characteristicsof one or more carrier frequencies adjacent to each one of the one ormore first unused frequencies; (c) selecting a first transmissionfrequency of the one or more transmission frequencies from the one ormore first unused frequencies at least partially based on the firstcharacteristics of the one or more carrier frequencies adjacent to eachone of the one or more first unused frequencies; and (d) broadcastingelectrical signals over the first transmission frequency of the one ormore transmission frequencies.

In various embodiments, a method of automatically selecting atransmission frequency from three or more potential carrier frequenciescan include: (a) scanning the three or more potential carrierfrequencies to determine a first signal strength indication of each ofthe three or more potential carrier frequencies; (b) rescanning thethree or more potential carrier frequencies to determine a second signalstrength indication of each of the three or more potential carrierfrequencies; (c) choosing the transmission frequency from the three ormore potential carrier frequencies at least partially based on the firstsignal strength indication and the second signal strength indication ofeach of the three or more potential carrier frequencies; and (d)transmitting electrical signals on the transmission frequency.

In many embodiments, a method of identifying a transmission frequencycan include: (a) at a first location, identifying a first frequency as afirst possible transmission frequency; (b) identifying the firstfrequency as the transmission frequency; (c) at a second location,automatically identifying a second frequency as a possible transmissionfrequency; and (d) identifying the second frequency as the transmissionfrequency.

Some embodiments concern a method of broadcasting one or more electricalsignals from an electrical device. The method can include: (a) using theelectrical device to select a first empty transmission frequency fromthe set of carrier frequencies; (b) using the electrical device totransmit identifying information for the first empty transmissionfrequency to the receiver over a second carrier frequency in the set ofcarrier frequencies; and (c) using the electrical device to transmit theone or more electrical signals over the first empty carrier frequency.

Numerous embodiments concern a method of broadcasting two or moreelectrical signals using a first electrical device. Each of the one ormore electrical signals includes radio broadcast data system data on asubcarrier frequency. The method includes: (a) using the firstelectrical device to identify a first radio frequency from one or moreradio frequencies in a first location at a first time using at least oneof: (1) characteristics of at least two radio frequencies of the one ormore radio frequencies; and (2) characteristics of one or more radiofrequencies adjacent to each of the at least two radio frequencies ofthe one or more radio frequencies; (b) using the first electrical deviceto transmit identifying information for the first radio frequency aspart of the radio broadcast data system data of at least a firstelectrical signal of the two or more electrical signals, the identifyinginformation transmitted over a second radio frequency of the one or moreradio frequencies; and (c) using the first electrical device to transmitat least a second electrical signal of the two or more electricalsignals over the first radio frequency.

In some embodiments, an electrical device configured to select atransmission frequency from a set of carrier frequencies for a user caninclude: (a) a receiver; (b) a scanning module configured to measure asignal strength indication of each carrier frequency in the set ofcarrier frequencies; (c) a scoring module configured to determine atleast one empty frequency based at least partially on the signalstrength indication of each carrier frequency in the set of carrierfrequencies; (d) a selection module configured to choose thetransmission frequency from the at least one empty frequency; and (e) atransmitter configured to transmit electrical signals.

The same or different embodiments can also concern an electrical deviceconfigured to be coupled to a vehicle. The vehicle can have a power plugwith a ground connector. The electrical device can include: (a) aconnector comprising a ground electrode and configured to electricallycouple to the vehicle; and (b) a transmitter electrically coupled to theconnector and configured to transmit first electrical signals using thevehicle as a radio antenna. When the ground electrode of the connectoris coupled to the ground connector of the power plug of the vehicle, thetransmitter can be configured to use the vehicle as the radio antenna.

Various embodiments can concern a radio frequency receiving apparatusconfigured to couple to a cigarette lighter of a vehicle. The cigarettelighter can include a first terminal and a ground terminal with theground terminal of the cigarette lighter electrically coupled to a bodyof the vehicle. The radio frequency receiving apparatus can include: (a)a cigarette lighter adapter can have: (1) a first contact configured tocouple to the first terminal of the cigarette lighter when the cigarettelighter adapter is inserted into the cigarette lighter; and (2) a secondcontact configured to couple to the ground terminal of the cigarettelighter when the cigarette lighter adapter is inserted into thecigarette lighter; and (c) a radio frequency receiver electricallycoupled to the second contact of the cigarette lighter adapter such thatthe body of the vehicle acts as an antenna for the radio frequencyreceiver when the cigarette lighter adapter is inserted into thecigarette lighter.

Turning to the drawings, FIG. 1 is a block diagram of an example of anelectrical device 100 configured to receive one or more electricalsignals from at least one source 190 and to transmit the one or moreelectrical signals to at least one receiving device 195, according to afirst embodiment. Electrical device 100 is merely exemplary and theinvention is not limited to the specific embodiments or examplespresented herein. Electrical device 100 can be employed in manydifferent embodiments or examples not specifically depicted or describedherein.

As an example, electrical device 100 can include: (a) transmissionfrequency identification system 101; (b) at least one receiver 102; (c)at least one transmitter 103; (d) a user communications component 104;(e) an external antenna matching circuit 105; (f) a power unit 106; and(g) at least one antenna 107. In some embodiments, electrical device 100can be coupled (removably or otherwise) to an external antenna 108 inaddition to or instead of antenna 107. In the same or differentexamples, user communications component 104 can include: (a) a display121; (b) an input coupling 122; and (c) user controls 125.

Broadly speaking, and as explained in detail below, in some embodiments,electrical device 100 can be coupled to and receive audio and/orelectrical signals from source 190 through input coupling 122. Before orwhile receiving audio and/or electrical signals from source 190,identification system 101 can identify a transmission frequency from aset of carrier frequencies. The transmission frequency can be a carrierfrequency selected to ensure that the audio and/or other electricalsignals from source 190 are transmitted over an unused or empty carrierfrequency.

After selecting the transmission frequency, display 121 displays thetransmission frequency to the user, and transmitter 103 beginstransmitting the audio and/or other electrical signals over thetransmission frequency using antenna 107 or external antenna 108. Theuser can turn the vehicle's radio to the displayed transmissionfrequency displayed by display 121 to receive the audio and/or otherelectrical signals. Accordingly, electrical device 100 allows a user toplay audio and/or other electrical signals from source 190 through hisvehicle's radio and speaker system without the distraction andfrustration of trying to manually locate an unused or empty carrierfrequency.

In some embodiments, source 190 is an electrical device configured toproduce electrical signals. For example, source 190 can be a mobile (orcellular) phone, a laptop computer, an audio playback device, a portableAM (amplitude modulated) and FM (frequency modulated) radio, a satelliteradio, a portable CD (compact disk) player, a data storage device, anaudio player, an audio-visual player, and/or a portable MP3 (MPEG AudioLayer-3) player. In other embodiments, source 190 can be part of orintegrally formed with electrical device 100. For example, electricaldevice 100 could include an MP3 player. Moreover, the electrical signalscan be audio signals, video signals, data signals, or other types ofelectrical signals. The term “source 190” includes electronic devices ofall types and designs, including, but not limited to, audio players andaudio-visual media players. Receiving device 195 can be any electricaldevice that includes a receiver capable of receiving radio frequency (orother high frequency) signals. In some embodiments, receiving device 195can be a radio or more specifically, a car radio.

In some examples, the set of carrier frequencies can include the full FMband. In the United States (US), the FM band includes the frequencies orchannels between 87.5 MHz (megahertz) and 108 MHz. In Japan, the FM bandincludes frequencies between 76 MHz and 90 MHz. In Europe, the FM bandincludes frequencies between 87.6 MHz and 107.9 MHz. In other countries,the full FM band can scan other ranges of carrier frequencies.

In the United States, there is a 0.2 MHz spacing between adjacentcarrier frequencies. That is, the set of carrier frequencies include thefrequencies with a 0.2 MHz spacing (87.5 MHz, 87.7 MHz, 87.9 MHz, etc.)In Japan and Europe, the spacing between adjacent carrier frequencies is0.1 MHz. In other embodiments, the set of carrier frequencies includes asubset of the full FM band. In further embodiments, the set of carrierfrequencies include other carrier frequency sets or bands (e.g., the AM(amplitude modulated), the VHF (very high frequency), or the UHF (ultrahigh frequency) band).

Turning back to FIG. 1, display 121 can be used to provide informationto the user of electrical device 100. In some examples, display 121 is aliquid crystal display (LCD) or indicator lights. Display 121 can becoupled to identification system 101 and configured to visually displaythe transmission frequency before and during transmission of electricalsignals over the transmission frequency by transmitter 103.

Input coupling 122 can be configured to couple electrical device 100 tosource 190. In some examples, input coupling 122 can receive electricalsignals (e.g., audio or other media) from source 190. Usercommunications component 104 can communicate the electrical signals totransmitter 103.

In the same or different embodiments, input coupling 122 can transfercommunication, power, and audio signals between electrical device 100and source 190. The type of input coupling 122 depends on the type ofconnector sources that electrical device 100 is designed to accept. Forexample, input coupling 122 can include a thirty-pin male serialconnector configured to be plugged into and electrically coupled to anApple® iPod® device. In another example, source 190 has a female USB(universal serial port) connector for coupling with external devices. Inanother example, input coupling 122 is a male USB connector.

User controls 125 allow the user to interact with and control electricaldevice 100. In some examples, user controls 125 can be configured toallow a user to select a new unused frequency. User controls 125 shouldbe broadly understood to refer to any type of mechanism (with or withoutmoving parts) with which the user can input information and/orinstructions to electrical device 100. For example, user controls 125can be a mechanical pushbutton, an electrostatic pushbutton, anelectrostatic array, a voice activated component, a touch screen, or anyother input component of any type.

Transmitter 103 can transmit electrical signals using antenna 107. Insome examples, receiver 102 receives electrical signals using antenna107. In other embodiments, electrical device 100 sends and/or receiveselectrical signals using external antenna 108.

To comply with FCC (Federal Communications Commission) and otherregulatory body requirements, the output of transmitter 103 can becoupled to an attenuation circuit (not shown). The amount of attenuationthat is needed to comply with FCC and other regulatory body requirementsis dictated by the output of the particular transmitter the quality andtype of antenna that is being utilized, and the environment in whichtransmitter 103 is being used. Consequently, the specific design of theattenuation circuit is a matter of design choice depending upon theneeds of the particular application. For some types of electricalsignals to be broadcast by transmitter 103, an attenuation circuit willnot be needed. In some embodiments, the attenuation circuit can be aportion of external antenna matching circuit 105.

Identification system 101 can be configured to select a transmissionfrequency from a set of carrier frequencies. Identification system 101can also be considered a system configured to identify at least onecarrier frequency in a set of carrier frequencies for use withtransmitter 103. That is, identification system 101 (or electricaldevice 100) can be a system for selecting a transmission frequency usedto transmit an electrical signal from source 190 to receiving device195. Identification system 101 is merely exemplary and the invention isnot limited to the specific embodiments or examples presented herein.Identification system 101 can be employed in many different embodimentsor examples not specifically depicted or described herein.

As an example, identification system 101 can include: (a) aninitialization module 111 configured to initialize electrical device100; (b) a scanning module 112 configured to measure a signal strengthindication of each carrier frequency in the set of carrier frequencies;(c) a scoring module 113 configured to determine at least one emptyfrequency based at least partially on the signal strength indications ofeach carrier frequency in the set of carrier frequencies; (d) aselection module 114 configured to choose the transmission frequencyfrom the at least one empty frequency; (e) a communications module 115configured to communicate the transmission frequency to the user; and(f) memory 116.

In some embodiments, initialization module 111, scanning module 112,scoring module 113, a selection module 114, and communications module115 can be implemented by program instructions stored in memory 116, andexecuted on a microprocessor (not shown), a microcontroller (not shown),or other electronic circuitry (not shown) in electrical device 100. Inother examples, one or more of initialization module 111, scanningmodule 112, scoring module 113, selection module 114, and communicationsmodule 115 can be implement by logic circuitry in electrical device 100.

Memory 116 can store one or more data elements used by electrical device100 or identification system 101. For example, memory 116 can store,among other things, one or more variables, values, arrays, or dataelements related to the selection of a transmission frequency. Invarious examples, memory 116 can include Flash memory or RAM (randomaccess memory).

FIG. 2 is a flow chart illustrating an example of a method 200 ofidentifying at least one transmission frequency from the set of carrierfrequencies to use with electrical device 100 (FIG. 1), according to thefirst embodiment. Method 200 or a portion thereof can also be considereda method for automatically selecting two or more transmissionfrequencies from three or more potential transmission frequencies.Method 200 or a portion thereof can further be considered a method ofselecting a transmission frequency from two or more carrier frequencies.Method 200 is merely illustrative of a technique for implementing thevarious aspects of certain embodiments described herein, and electricaldevice 100 (FIG. 1) and method 200 are not limited to the particularembodiments described herein, as numerous other embodiments arepossible.

In some examples, when electrical device 100 (FIG. 1) is running,program instructions, stored in memory 116 (FIG. 1), are executed by amicroprocessor, a microcontroller, or other electronic circuitry. Aportion of the program instructions can be suitable for carrying out themethod of identifying at least one transmission frequency from the setof carrier frequencies with electrical device 100 (FIG. 1) as describedbelow with respect to FIGS. 2-7. In other examples, method 200 orportions thereof can be implemented using by logic circuitry inelectrical device 100.

In the example illustrated in FIG. 2, a first activity in method 200 isan activity 251 determining whether electrical device 100 (FIG. 1) iscoupled to source 190 (FIG. 1). Referring again to the example shown inFIG. 1, initialization module 111 is configured to attempt tocommunicate with source 190 through input coupling 122, as part (notshown), antenna 107, or antenna 108. In some examples, a coupling withsource 190 is detected by initialization module 111 when aninitialization or handshaking routine with source 190 is initiated orcompleted.

Referring again to FIG. 2, if electrical device 100 (FIG. 1) is notcoupled to source 190 (FIG. 1), the next activity in method 200 is anactivity 253 of electrical device 100 (FIG. 1) going into an idle state.Electrical device 100 (FIG. 1) stays in the idle state until electricaldevice 100 (FIG. 1) detects a coupling to source 190 (FIG. 1). In oneexample, initialization module 111 (FIG. 1) can attempt to communicatewith source 190 (FIG. 1) by repeating activity 251 at predetermined timeintervals (e.g., two or five seconds) until a connection with source 190(FIG. 1) is detected.

If electrical device 100 (FIG. 1) is coupled to source 190 (FIG. 1), thenext activity in method 200 is an activity 252 of determining whetherelectrical device 100 (FIG. 1) is being powered on for the first time.In some examples, if electrical device 100 (FIG. 1) is being powered onfor the first time, electrical device 100 (FIG. 1) might need to beinitialized. In various embodiments, being powered on for the first timecan include starting electrical device 100 (FIG. 1) for the first timeor restarting electrical device 100 (FIG. 1) after electrical device 100has been turned off or reset. In other examples, powered on for thefirst time includes only starting electrical device 100 (FIG. 1) for thefirst time after manufacturing or after a system reset.

If electrical device 100 (FIG. 1) is being powered on for the firsttime, the next activity in method 200 of FIG. 2 is an activity 254 ofinitializing identification system 101 (FIG. 1). In some examples,initializing identification system 101 (FIG. 1) includes setting one ormore variables to predetermined values. For example, all the variables,grades, or ratings in a signal strength array can be set to one or morepredetermined values (e.g., zero or −6 or −4).

The signal strength array is a list of the carrier frequencies in theset of carrier frequencies and a corresponding value, grade, or ratingof the signal strength of the carrier frequencies. In one example, eachof the carrier frequencies is assigned a weighted signal strength valueof −6 to +5. In other examples, other valuing, grading, or ratingsystems of the signal strengths of the carrier frequencies can be used.

In some examples, a carrier frequency can be considered to have a signalon the carrier frequency or be a used channel if the signal strengthvalue is between −3 and +5. A carrier frequency can be considered anunused and/or empty carrier frequency if the signal strength value isbetween −6 and −4. The range of signal strength values and whatqualifies as an unused and/or empty carrier frequency can vary from theexamples provided herein. In some examples, an RSSI (received signalstrength indication) value for each carrier frequency is also stored inthe signal strength array. The RSSI value is a measure of the strengthof electrical signals on a carrier frequency.

Referring again to FIG. 2, the next activity in method 200 is anactivity 255 of identifying one or more unused carrier frequencies inthe set of carrier frequencies. FIG. 3 is a flow chart illustrating anexample of activity 255 of identifying one or more unused carrierfrequencies in the set of carrier frequencies, according to the firstembodiment.

Referring to FIG. 3, the first procedure in activity 255 is a procedure371 of adjusting the signal strength array values. In one example, eachsignal strength value in the signal strength array that is above aminimum value is decreased by one, and each signal strength value in thesignal strength array that is less than or equal to the minimum value isnot changed. For example, if the signal strength array value for onecarrier frequency is −1 and if the minimum value is −3, the signalstrength value is decreased to −2. In some examples, scanning module 112(FIG. 1) can adjust the signal strength array values stored in memory116 (FIG. 1).

Adjusting the signal strength values allows the results of previousattempts to identify unused carrier frequencies to be considered indetermining unused carrier frequencies but with the results of previousattempts given a decreased weight. For the first attempt to identifyunused frequencies, the signal strength array values are decreased onefrom the initial value. However, in subsequent iterations, the signalstrength array values are not reset to the initial value and, instead,have values determined by the previous attempts. Accordingly, theresults of previous attempts can affect the signal strength valuesstored in the signal strength array. In alternative embodiments, thesignal strength values are reset to a predetermined default value at thebeginning of each attempt to identify unused carrier frequencies, andthe results of previous iterations do not affect the current results.

Referring again to FIG. 3, the next procedure in activity 255 is aprocedure 372 of scanning the set of carrier frequencies. In someembodiments, procedure 372 can be considered scanning the set of carrierfrequencies for unused carrier frequencies. FIG. 4 is a flow chartillustrating an example of procedure 372 of scanning the set of carrierfrequencies, according to the first embodiment.

Referring to FIG. 4, the first process in procedure 372 is a process 481of tuning to an initial carrier frequency in the set of carrierfrequencies. Referring back to FIG. 1, in some embodiments, scanningmodule 112 can instruct receiver 102 to tune to the highest carrierfrequency in the set of carrier frequencies. When the set of carrierfrequencies is the full United States FM band, scanning module 112 caninstruct receiver 102 to tune to 107.9 MHz. In other embodiments,scanning module 112 can instruct receiver 102 to tune to the lowestcarrier frequency or another predetermined carrier frequency. Forexample, the carrier frequency can be tuned to the frequency 0.2 MHzbelow the highest frequency when the set of carrier frequencies is thefull United States FM band.

Referring again to FIG. 4, the next process in procedure 372 is aprocess 482 of seeking the next carrier frequency in the set of carrierfrequencies. Seeking includes tuning receiver 102 (FIG. 1) to the nextcarrier frequency in the set of carrier frequencies and measuring theRSSI value. In some examples, receiver 102 (FIG. 1) measures the RSSIvalue for the carrier frequency. In some examples, the inverse RSSIvalue can be measured instead of the RSSI value. As appropriate herein,“RSSI value” refers to the RSSI value and/or the inverse RSSI value.

In some embodiments, if the scanning has just begun, receiver 102(FIG. 1) is tuned to the second highest carrier frequency (e.g., 107.7MHz in the US) in procedure 372, and the RSSI value at 107.7 MHzfrequency is measured.

In the same or different embodiments, the RSSI value for the highest (orlowest) carrier frequency in the set of carrier frequency is notmeasured because the highest carrier frequency can be more prone tointerference than other carrier frequencies. In alternative embodiments,receiver 102 can measure the RSSI value for the highest carrierfrequency band in process 482.

The next process in procedure 372 is a process 484 of determining if theseeking is complete. Seeking is complete if the RSSI value measured inprocess 482 is greater than a predetermined value (e.g., the RSSIthreshold). The RSSI threshold is the maximum value of signal strengthacceptable on a carrier frequency for the carrier frequency to beconsidered useable, available, or empty. If the RSSI value is greaterthan the RSSI threshold for a carrier frequency, a radio station oranother electrical device is probably already broadcasting on thiscarrier frequency, or a signal on an adjacent carrier frequency isbleeding into this carrier frequency. In some examples, the RSSIthreshold can be 100 dBuV (decibels relative to 1 micovolt).

In some examples, receiver 102 (FIG. 1) determines if the RSSI value isgreater than the RSSI threshold. In other examples, receiver 102(FIG. 1) communicates the RSSI value to scanning module 112 (FIG. 1),and scanning module 112 (FIG. 1) determines if the value is greater thanthe RSSI threshold.

If seeking is complete (process 484), the next process in procedure 372is a process 485 of reading the current carrier frequency. In oneexample, receiver 102 (FIG. 1) determines the current carrier frequencyand communicates the carrier frequency to scanning module 112 (FIG. 1).

The next process in procedure 372 is a process 486 of adjusting thesignal strength array value corresponding to the current carrierfrequency. In some examples, process 486 can be considered providing agrade, value, or rating for the carrier frequency at least partiallybased on results of the scanning of the set of the carrier frequencies.In some embodiments, scanning module 112 (FIG. 1) can read the signalstrength value for this carrier frequency from the array of signalstrength values stored in memory 116 (FIG. 1) and adjust the signalstrength value accordingly.

For example, as part of process 486, if the signal strength array valuecorresponding to the current carrier frequency is less than four,scanning module 112 (FIG. 1) can increase the signal strength value bytwo. If the corresponding signal strength value is equal to or greaterthan four, scanning module 112 (FIG. 1) can set the signal strengthvalue equal to five. In other examples, scanning module 112 (FIG. 1) orother modules in identification system 101 (FIG. 1) can adjust thesignal strength array values by other amounts.

The subsequent process in procedure 372 is process 483 of determining ifthe end of the set of carrier frequency has been reached. For example,the end of the set of carrier frequencies can be reached when receiver102 (FIG. 1) and/or scanning module 112 (FIG. 1) has determined the RSSIvalue for every carrier frequency in the set of carrier frequencies. Asanother example, the end of the set of carrier frequencies is reachedwhen receivers (102 (FIG. 1) and/or scanning module 112 (FIG. 1) reachesthe lowest carrier frequency (e.g., 87.5 MHz). In some examples,receiver 102 (FIG. 1) determines if the end of the set of carrierfrequencies is reached. In other examples, scanning module 112 (FIG. 1)determines if the end of the set of carrier frequencies has beenreached.

If the end of the set of frequencies is reached, procedure 372 andactivity 255 (FIG. 2) are complete, and the next is an activity 256(FIG. 2). If the last carrier frequency has not been reached, processes482 and 483 are repeated for the next carrier frequency. For example, inthe United States, if the current frequency is 107.7 MHz, the nextcarrier frequency is 107.5 MHz. In a different embodiment, processes481-486 can scan the frequencies from the lowest frequency to thehighest frequency or using any predetermined order.

Returning to process 484, if seeking is not complete (i.e., the RSSIvalue is less than or equal to a predetermined value), then the signalstrength array value for the current carrier frequency is not adjusted.Instead, process 483 is performed.

Referring again to FIG. 2, after activity 255 is complete, the nextactivity in method 200 is an activity 256 of determining the emptycarrier frequencies. FIG. 5 is a flow chart illustrating an example ofactivity 256 of determining the empty carrier frequencies, according tothe first embodiment.

Referring to FIG. 5, the first procedure in activity 256 is a procedure570 of selecting a test unused frequency. In some embodiments, scoringmodule 113 (FIG. 1) can select the highest unused carrier frequency(e.g., 107.9 MHz) as the first test unused frequency. In some examples,the highest (or lowest) unused carrier frequency is disregarded becausea higher adjacent frequency (e.g., 108.1 MHz) is not in the set ofcarrier frequencies and/or because the highest (or lowest) frequency ismore prone to interference. In other examples, the highest (or lowest)unused frequency is treated the same as any other unused carrierfrequencies. In subsequent selection procedures, test frequencies can beselected by checking each carrier frequency in a predetermined orderwhether the frequency is unused. For example, if the signal strengthvalue for the carrier frequency is between −6 and −4, the carrierfrequency can be considered an unused carrier frequency.

After selecting the test unused carrier frequency, the next procedure inactivity 256 is a procedure 571 of determining if the carrierfrequencies adjacent to the test unused frequency are also unusedcarrier frequencies. For example, if the test unused frequency is 107.1MHz, scoring module 113 (FIG. 1) can determine whether 106.9 MHz and107.3 MHz are unused frequencies. As mentioned above, in someembodiments, a carrier frequency is considered unused if the signalstrength value for the carrier frequency is between −6 and −4. In someexamples, scoring module 113 (FIG. 1) reads the signal strength value ofthe adjacent frequencies from memory 116 (FIG. 1).

If the adjacent frequencies are not unused frequencies, the nextprocedure in activity 256 is a procedure 572 of determining whether thetest unused frequency is the last unused carrier frequency. If the testunused frequency is the last test unused frequency, activity 256 iscomplete, and the next activity is activity 257 (FIG. 2). In someembodiments, scoring module 113 (FIG. 7) determines if the test unusedfrequency is the last test unused carrier frequency by checking thesignal strength to values in the signal strength array.

If the test unused carrier frequency is not the last unused carrierfrequency, the next procedure in activity 256 is the procedure 573 ofselecting the next test unused carrier frequency. After the next testunused carrier frequency is selected, the next procedure in activity 256is procedure 571.

Returning to procedure 571, if the carrier frequencies adjacent to thetest unused frequency are also unused carrier frequencies, the nextprocedure in activity 256 is a procedure 574 of determining if the RSSIvalue of the test unused frequency and adjacent frequencies are withinan acceptable relative range. In one example, the RSSI value of the testunused frequency and the RSSI values of the adjacent carrier frequenciesmust be within a predetermined amount of each other. For example, if thetest unused frequency has an RSSI equal to 25, if the adjacent carrierfrequencies have RSSI equal to 5, and if the predetermined amount isequal to 10, the test unused frequency will be disqualified because theRSSI (25) of the test unused frequency is not within the predeterminedamount (10) of the RSSI (5) of the adjacent carrier frequencies. If theRSSI of the adjacent frequencies were 23, instead 5, then the testunused frequency would be acceptable. This test is performed because thetest unused frequency or the adjacent frequencies might not be a clearchannel when compared to each other. That is, if an adjacent frequencyhas a relatively strong signal, this strong signal could bleed over toand interfere with the test unused carrier frequency.

In various examples scoring module 113 (FIG. 1) can determine if theRSSI value of the test unused frequency is within the acceptablerelative range. In the same or different embodiments, if the RSSI valueof the test unused frequency is not within an acceptable relative range,it is disqualified as a potential transmission frequency, and the nextprocedure in activity 256 is procedure 572.

If the RSSI value of the test unused frequency and the adjacentfrequencies are within an acceptable relative range, the next procedurein activity 256 is a procedure 575 of determining whether the RSSIvalues of the test unused frequency and the adjacent frequencies arewithin an acceptable absolute range. For example, if the test unusedfrequency has an RSSI equal to 6, if the adjacent carrier frequencieshave RSSI equal to 17 and 19, and if the predetermined maximum absoluteRSSI value is equal to 10, the test unused carrier frequency will bedisqualified because the RSSI (17 and 19) of the adjacent carrierfrequencies is above the predetermined maximum absolute RSSI value (10).If the RSSI of the adjacent carrier frequencies was 10, the test unusedfrequency would be acceptable. This test is performed because thecarrier frequency might be a clear channel when compared to the adjacentcarrier frequencies but not when compared to an absolute RSSI value. Invarious examples, scoring module 113 (FIG. 1) can determine if the RSSIvalues of test unused frequency and adjacent carrier frequencies arewithin an acceptable range.

In some embodiments, the order of procedures 574 and 575 can be reversedor only one of procedures 574 and 575 can be performed.

If the RSSI values of adjacent carrier frequencies are not within anacceptable absolute range in procedure 575, the next procedure inactivity 256 is procedure 572 of determining whether the test unusedfrequency is the last unused carrier frequency.

If the RSSI values of adjacent carrier frequencies are within anacceptable absolute range in procedure 575, the next procedure inactivity 256 is a procedure 576 of storing the test unused frequency inan available frequency list. In various examples, scoring module 113(FIG. 1) can save the test unused frequency into the available frequencylist stored in memory 116 (FIG. 1). In some embodiments, the RSSI valuefor the test unused frequency is saved along with the test unusedfrequency in the available frequency list.

After storing the test unused frequency in the available frequency list,the next procedure in activity 256 is procedure 572 of determiningwhether the test unused frequency is the last unused carrier frequency.If the test unused carrier frequency is the last unused carrierfrequency, activity 256 is complete, and the next activity is anactivity 257 (FIG. 2).

Referring again to FIG. 2, after activity 256 is complete, the nextactivity in method 200 is activity 257 of ranking the empty carrierfrequencies. Ranking the frequencies helps ensure that a user isprovided the clearest frequencies for use with electrical device 100(FIG. 1). In yet other embodiments, activity 257 can be skipped, and thetransmission frequency can be selected from the carrier frequencies inthe available frequency list. FIG. 6 is a flow chart illustrating anexample of activity 257 of ranking the empty carrier frequencies,according to the first embodiment.

Referring to FIG. 6, the first procedure in activity 257 is a procedure671 of tuning to the first empty carrier frequency in the availablecarrier frequency list. In some examples, selection module 114 (FIG. 1)can instruct receiver 102 (FIG. 1) to tune into the first empty carrierfrequency.

The next procedure in activity 257 is a procedure 672 of determining theproperties of the empty carrier frequency. In one example, at least oneof the RSSI value, the SNR (signal-to-noise ratio), and the impulsedetection value for the empty carrier frequency can be measured. In someexamples, receiver 102 (FIG. 1) can determine these values andcommunicate the properties to selection module 114 (FIG. 1). In otherembodiments, one or more of these values were previously determined inprocess 482 (FIG. 4).

The SNR is the ratio of the signal power to the noise power corruptingthe signal. That is, the SNR compares the level of the desired signal tothe level of background noise. The higher the ratio, the less thebackground noise. Accordingly, the SNR threshold is the minimum value ofthe ratio of signal power to noise power that is acceptable on a carrierfrequency for the carrier frequency to be considered useable, available,or empty.

Impulse noise can interfere with radio frequency signals and can rendera radio frequency unusable. Accordingly, radio frequencies with lowerimpulse noise are better transmission frequencies. Impulse noise can becaused by various environmental factors including the ignition system ofa vehicle or other DC (direct current) motors. Accordingly, the impulsedetection threshold is the maximum value of impulse noise acceptable ona carrier frequency for the carrier frequency to be considered useable,available, or empty.

In some example, the SNR threshold can be set to one, and the impulsedetection threshold can be set to zero. In other embodiments, othervalues or variables can be used.

After determining these value(s) in procedure 672, the next procedure inactivity 257 is a procedure 673 of determining whether the SNR ratio isless than a SNR threshold. In some examples, selection module 114(FIG. 1) can determine whether the SNR ratio is greater than the SNRthreshold. If the SNR ratio is too high, the carrier frequency isunsuitable to use with electrical device 100 (FIG. 1).

If the SNR value is greater than the SNR threshold, the next procedurein activity 257 is a procedure 675 of removing the empty carrierfrequency from the available carrier frequency list. In some examples,selection module 114 (FIG. 1) can remove the empty carrier frequencyfrom the available carrier frequency list.

After removing the empty carrier frequency, the next procedure inactivity 257 is a procedure 676 of determining whether the empty carrierfrequency was the last carrier frequency in the available carrierfrequency list. If the empty carrier frequency was not the last carrierfrequency in the available carrier frequency list, the next procedure inactivity 257 is procedure 677 of tuning to the next carrier frequency inthe available carrier frequency list. After tuning to the next carrierfrequency (procedure 677), the next procedure is procedure 672 ofdetermining the properties of this next empty carrier frequency.

If the SNR ratio is less than the SNR threshold in procedure 673, thenext procedure in activity 257 is procedure 674 of determining if theimpulse detection value for the carrier frequency is less than theimpulse detection threshold. In one example, selection module 114(FIG. 1) can determine if the impulse detection value for the emptyfrequency is greater than the impulse detection threshold.

If the impulse detection value for the empty carrier frequency isgreater than the impulse detection threshold, the next procedure inactivity 257 is procedure 675 of removing the empty carrier frequencyfrom the available carrier frequency list.

In other embodiments, the order of procedures 673 and 674 can bereversed, or only one of procedures 673 and 674 can be performed. Instill other embodiments, one or both of procedures 673 and 674 can beperformed as part of activity 256. In a further embodiment, both ofprocedures 673 and 674 can be omitted from activity 257, and instead,activity 257 can start with procedure 678.

If the impulse detection value for the empty carrier frequency is lessthan the impulse detection threshold, the next procedure in activity 257is procedure 676 of determining whether the empty carrier frequency wasthe last carrier frequency in the available carrier frequency list. Ifthe empty carrier frequency was not the last carrier frequency in theavailable carrier frequency list, the next procedure in activity 257 isprocedure 677 of tuning to the next carrier frequency in the availablecarrier frequency list.

If the empty carrier frequency was the last carrier frequency in theavailable carrier frequency list, the next procedure in activity 257 isa procedure 678 of reordering the available carrier frequency list. Insome examples, selection module 114 (FIG. 1) can reorder the availablecarrier frequency list in descending order of RSSI values. The availablecarrier frequencies can be reordered to ensure the clearest carrierfrequency is provided first to the user.

After procedure 678, the next procedure in activity 257 is a procedure679 of eliminating carrier frequencies with unacceptable RSSIdifferences from the available carrier frequency lists. In variousembodiments, carrier frequencies with an RSSI value larger by more thana predetermined amount than the smallest RSSI value are removed from thelist. For example, if the available carrier frequency list had fivecarrier frequencies, if their RSSI values are 2, 3, 5, 6 & 11,respectively, and if the predetermined amount is four, then the channelwith RSSI equal to 11 will be eliminated from the array because the RSSIvalue (11) of that carrier frequency was larger than the smallestinverse RSSI value (2) by more than the predetermined amount (4). Theother frequencies with RSSI values of 3, 5 and 6 are within theacceptable range and, accordingly, left in the available carrierfrequency list, along with the frequency with the RSSI value of 2. Thisprocedure will eliminate carrier frequencies that have either acceptableRSSI values when compared to adjacent carrier frequencies or acceptableabsolute RSSI values, but are still unacceptable because their RSSIvalues are too large when compared to the RSSI values of other currentlyavailable carrier frequencies.

In some examples, selection module 114 (FIG. 1) can remove the carrierfrequencies from the available carrier frequency list. In otherembodiments, other criteria can be used to remove carrier frequencieswith comparatively large RSSI values. For example, carrier frequencieswith RSSI values larger than the average or median RSSI values for thecarrier frequencies in the available carrier frequency list could beremoved. In still other embodiments, procedure 679 is not performed.

After procedure 679, the next procedure in activity 257 is a procedure680 of copying the available carrier frequency list into a workingcarrier frequency list. Use of a double buffer for the list of availablecarrier frequencies allows identification system 101 (FIG. 1) to updatethe list while keeping a list of values available for immediate use bythe user. As a result of the double buffer system and running method 200as a background task, a carrier frequency is always immediatelyavailable to the user after the initial configuration. In otherembodiments, a double buffer system is not used, and only one list (i.e.the available carrier frequency list) is used.

After copying the available carrier frequency list, activity 257 iscomplete and the next activity in method 200 (FIG. 2) is an activity 258(FIG. 2) of determining if the user has requested a transmissionfrequency. In one example, a user can use user controls 125 (FIG. 1) inuser communications component 104 (FIG. 1) to request a transmissionfrequency. In one example, if the user requests a transmission frequencythrough user controls 125 (FIG. 1) (e.g., by pressing a button), usercommunications component 104 (FIG. 1) can communicate the request tocommunications module 115 (FIG. 1).

Referring again to FIG. 2, if the user requests a transmissionfrequency, the next activity in method 200 is an activity 260 ofobtaining a transmission frequency for the user. FIG. 7 is a flow chartillustrating an example of activity 260 of obtaining a transmissionfrequency for the user, according to the first embodiment.

Referring to FIG. 7, the first procedure in activity 260 is a procedure771 of retrieving a transmission frequency from the working carrierfrequency list. In some embodiments, if this request is the firstrequest for a transmission frequency, the carrier frequency with thelowest RSSI value (i.e., the first carrier frequency in the workingcarrier frequency list) is retrieved. In some embodiments, the retrievedcarrier frequency is the carrier frequency with the lowest RSSI valuenot previously used. In some examples, communications module 115(FIG. 1) can retrieve the transmission frequency from the workingcarrier frequency list stored in memory 116 (FIG. 1).

After retrieving the transmission frequency, the next procedure inactivity 260 is a procedure 772 of providing the transmission frequencyto the user. Referring to FIG. 1, in some examples, communicationsmodule 115 can instruct user communications component 104 to display thetransmission frequency to the user. The transmission frequency can bedisplayed by display 121. In these examples, after the transmissionfrequency is displayed by display 121, the user can manually tune theradio to the transmission frequency. In another embodiment, usercommunications component 104 can provide the transmission frequency inan audible form.

In other examples, other methods can be used to provide the transmissionfrequency to the user. For example, receiving device 195 can beautomatically tuned to the transmission frequency. For example, FIG. 8is a flow chart illustrating an example of procedure 772 of providingthe transmission frequency to the user, according to an embodiment.

Referring to FIG. 8, the first process in procedure 772 is a process 881of displaying the transmission frequency. In some embodiments, usercommunications component 104 (FIG. 1) can display the transmissionfrequency to the user. The transmission frequency can be displayed bydisplay 121 (FIG. 1).

A subsequent process in procedure 772 is a process 882 of decidingwhether this request for a transmission frequency is the first requestfor a transmission frequency. In some embodiments, selection module 114can determine if this request for a transmission frequency is the firstrequest for a transmission frequency.

If this request is the first request for a transmission frequency, thenext process in procedure 772 is a process 883 of tuning the receivingdevice to the transmission frequency. In some examples, the usermanually tunes receiving device 195 (FIG. 1) to the transmissionfrequency. That is, the user of receiving device 195 (FIG. 1) can readthe transmission frequency from display 121 (FIG. 1) and manually tunereceiving device 195 (FIG. 1) to the transmission frequency.

If the request for a transmission frequency is not the first request fora transmission frequency, receiving device 195 (FIG. 1) can beautomatically tuned to the transmission frequency in some examples. Inthese examples, the next process in procedure 772 is a process 884 oftransmitting identifying information for the transmission frequency to areceiver or receiving device over a carrier frequency from the set ofcarrier frequencies. Referring again to FIG. 1, transmitter 103 cantransmit identifying information (e.g., the call numbers of thetransmission frequency) to receiving device 195.

In many examples, the identifying information can be transmitted fromtransmitter 103 to receiving device 195 over the old transmissionfrequency. That is, the user had previously requested a transmittingfrequency before the current request. Transmitter 103 is currentlybroadcasting the electrical signal over this old transmission frequency.In this example, transmitter 103 transmits the identifying informationover the old transmission frequency to receiving device 195.

In same or different examples, the identifying information istransmitted using a subcarrier frequency of a specific carrierfrequency. A subcarrier frequency is a separate analog or digital signalcarried on the carrier frequency, which can transmit extra informationbeyond the information transmitted by the main carrier frequency. In oneexample, the 57 KHz (kilohertz) subcarrier frequency of a standard FMfrequency can be used to transmit the identifying information for thenew transmission frequency.

In the same or different embodiments, the identifying information can betransmitted using the European Radio Data System standard or the UnitedStates' Radio Broadcast Data System standard (collectively, the “RDSstandards”). The RDS Standards includes the European Radio Data Systemstandard, the United States' Radio Broadcast Data System standard andany similar standards in other countries. RDS standards also include anysubsequent, succeeding, or competing standards to the RDS standards.

The RDS standards are standards for sending small amounts of digitalinformation in conventional FM radio broadcasts using a subcarrierfrequency. In some versions of the RDS standards, the informationtransmitted includes AF (Alternative Frequency) information. Typically,the AF data includes information about alternative frequencies on whichthe current radio station can be heard. Conventionally, radios can usethe AF data to tune the radio to the alternative frequency broadcastingthe same content when the signal on the current carrier frequency getstoo weak.

In some embodiments of process 884 of FIG. 8, instead of encodinginformation regarding other carrier frequencies broadcasting the sameradio station in the AF data, communications module 115 (FIG. 1) canencode identifying information for the newly requested transmissionfrequency into the AF data of the old (i.e. current) transmissionfrequency

After encoding the AF data with the transmission frequency, theelectrical signal with AF data can be broadcast over the old (i.e.,currently used) transmission frequency. In other embodiments, the AFdata is encoded and transmitted over a different predetermined carrierfrequency.

Referring still to FIG. 8, the next process in procedure 772 is aprocess 885 of receiving the identifying information using a receiver.In some embodiments, receiving device 195 is already tuned to the oldtransmission frequency and receives the identifying information encodedin the AF data for the old transmission frequency. In other examples,the identifying information can be encoded in the electrical signaltransmitted by other methods, and receiving device 195 can be designedand programmed to receive the identifying information.

After receiving the identifying information, the subsequent process ofprocedure 772 is a process 886 of tuning the receiver to thetransmission frequency. That is, receiving device 195 (FIG. 1) canautomatically tune to the transmission frequency. In some embodiments,receiving device 195 (FIG. 1) has the AF option activated and, when theidentifying information is received as part of the AF data, receivingdevice 195 (FIG. 1) automatically tunes the receiving device 195(FIG. 1) to the transmission frequency. If the AF option is notactivated, the user of receiving device 195 (FIG. 1) can manually tunereceiving device 195 (FIG. 1) to the transmission frequency, in a mannersimilar or identical as to the process described in process 883.

After process 886 of FIG. 8, procedure 772 is complete and the nextprocedure in activity 260 is a procedure 773 of setting (e.g., tuning) atransmitter such as, for example, transmitter 103 (FIG. 1) to transmiton the transmission frequency. In some embodiments, transmitter 103(FIG. 1) automatically begins to transmit on the transmission frequencyafter being set to transmit. In other examples, transmitter 103 (FIG. 1)waits a predetermined time (e.g., one or seven seconds) and then beginstransmitting. In alternative embodiments, transmitter 103 (FIG. 1) waitsfor instructions from the user to begin transmitting. In some examples,communications module 115 (FIG. 1) can instruct transmitter 103 (FIG. 1)to begin transmitting on the transmission frequency. In differentembodiments, procedure 773 (FIG. 7) can occur before procedure 772 (FIG.7).

Referring again to FIG. 7, after providing the transmission frequency tothe user in procedure 774, activity 260 can also mark the new currenttransmission frequency as used. In some examples, the working carrierfrequency list allows the carrier frequencies to be mark as used. Insome embodiments, if a carrier frequency is marked as used, this carrierfrequency will not be provided to the user again. In a differentembodiment, a carrier frequency from the working carrier frequency listwill not be provided again to a user unless method 200 (FIG. 2) isrepeated, beginning at activity 255 (FIG. 2), as explained hereafter. Insome examples, communications module 115 (FIG. 1) can mark thetransmission frequency as used. In other embodiments, marking thetransmission frequency as used can be performed by removing the carrierfrequency from the working carrier frequency list.

Referring again to FIG. 2, after procedure 774 (FIG. 7), activity 260 iscomplete, and the next activity in method 200 is an activity 259 ofdetermining if a predetermined time period has passed. In variousexamples, the predetermined time is seven seconds. If the predeterminedtime has passed, the next activity in method 200 is activity 255 ofidentifying unused carrier frequencies. That is, if the predeterminedtime has passed, the activities needed to identify new or additionaltransmission frequencies or to confirm the usability of the carrierfrequencies in the working carrier frequency list are repeated (i.e.,activities 255 through 257).

To ensure a clear transmission frequency, it preferable to repeatactivities 255 through 257 at regular intervals. If electrical device100 (FIG. 1) is moving (e.g., in a vehicle), the carrier frequenciesavailable for use are continuously changing. For example, if electricaldevice 100 (FIG. 1) was at the base of a tall building during theinitial scan, the building could have blocked a strong signal on one ormore carrier frequencies. As soon as electrical device 100 (FIG. 1)moves out of the shadow of the tall building, this carrier frequencywould no longer be an acceptable frequency for transmission.Accordingly, updating the working carrier frequency list after a shortpredetermined time ensures that the best transmission frequency ispresented to the user.

To one of ordinary skill in the art, it will be readily apparent thatthe device, system, apparatus, and method of use discussed herein may beimplemented in a variety of embodiments, and that the foregoingdiscussion of certain of these embodiments does not necessarilyrepresent a complete description of all possible embodiments. Forexample, identification system 101 (FIG. 1) does not have to use all thefiltering criteria (e.g., procedures 574-575 (FIG. 5), 673-674 (FIG. 6),and 678-679 (FIG. 6)) discussed herein to choose a transmissionfrequency. In some embodiments, only a subset of the filtering criteriaor other criteria can be used. For example, identification system 101(FIG. 1) could only use the SNR ratio and/or the impulse detection valueto filter out used carrier frequencies. In other embodiments,identification system 101 (FIG. 1) could only use the RSSI value (orinverse RSSI). In yet other embodiments, identification system 101 couldignore the RSSI values of adjacent carrier frequencies or use the SNR orimpulse detection value for the adjacent carrier frequencies asfiltering criteria.

In some embodiments, as previously explained, all of or a portion ofmethod 200 can be considered a method to choose the at least one carrierfrequency at least partially based upon the signal strength indicationof the at least one of the one or more unused carrier frequencies. Inthe same or different embodiments, all or a portion of method 200 can beconsidered a method to select a transmission frequency from the at leastone first frequency at least partially based on the characteristics ofthe carrier frequencies adjacent to each one of the at least one firstfrequency. Moreover, all of or a portion of method 200 can be considereda method to select at least one first frequency based on the ratings ofthe one or more carrier frequencies. Also, method 200 can be considereda method to choose a first transmission frequency of the one or morefirst potential carrier frequencies in the set of potential carrierfrequencies at least partially based on a received signal strengthindication of each of the one or more potential carrier frequencies andcharacteristics of neighboring frequencies of each of the one or morepotential carrier frequencies.

FIG. 9 is a front perspective representational view illustrating anexample of electrical device 100 coupled to source 190, according to thefirst embodiment. FIG. 10 is a block diagram illustrating an example ofthe coupling of receiver 102 to external antenna 108, according to thefirst embodiment. FIG. 11 is a circuit diagram illustrating an exampleof an external antenna matching circuit and other circuits in electricaldevice 100, according to the first embodiment.

In some examples, electrical device 100 can be considered a radiofrequency receiving apparatus configured to couple to a cigarettelighter on a vehicle 1070 (FIG. 10). In the same or differentembodiments, electrical device 100 can be considered an electricaldevice configured to be coupled to vehicle 1070.

In some examples, as illustrated in FIG. 10, vehicle 1070 can include:(a) external antenna 108; and (b) a power plug 1071. Power plug 1071 caninclude: (a) positive terminal 1072; and (b) a ground terminal 1073. Inmany vehicles, ground terminal 1073 of power plug 1071 is electricallycoupled to the exterior body of the automobile. In various embodiments,power plug 1071 can be a cigarette lighter.

In various examples, external antenna 108 can include the exterior bodyof vehicle 1070. In the same or different embodiment, external antenna108 can include the chassis of vehicle 1070. Usually vehicles have aseparate antenna that protrudes from the vehicle that is used to receiveFM signals for any attached radios, instead of using the exterior bodyof the vehicle as an antenna.

In various examples, power unit 106 (FIG. 1) can include: (a) a positiveelectrode or contact 1022 configured to couple to positive terminal 1072when power unit 106 or a portion thereof is inserted into or otherwisecoupled to power plug 1071; and (b) a ground electrode or contact 1023configured to couple to the ground terminal 1073 when power unit 106 ora portion thereof is inserted into or otherwise coupled to power plug1071. In some examples, power unit 106 can be or include a connector(e.g. cigarette lighter adapter) configured to couple to power plug1071.

Receiver 102 (FIG. 1) is electrically coupled to external antennamatching circuit 105 (FIG. 1). External antenna matching circuit 105(FIG. 1) can be electrically coupled between receiver 102 (FIG. 1) andvehicle 1070. In some examples, external antenna matching circuit 105and transmitter 103 are electrically coupled to the ground contact 1023.

When ground contact 1023 is coupled to ground terminal 1073, transmitter103 and/or receiver 102 are configured and coupled such that externalantenna 108 (e.g., the body of the vehicle 1070) acts as the antenna fortransmitter 103 and/or receiver 102. That is, in some embodiments,vehicle 1070 is used as a frequency modulated radio antenna fortransmitter 103 and/or receiver 102.

Although the invention has been described with reference to specificembodiments, it will be understood by those skilled in the art thatvarious changes may be made without departing from the spirit or scopeof the invention. Additional examples of such changes have been given inthe foregoing description. Accordingly, the disclosure of embodiments ofthe invention is intended to be illustrative of the scope of theinvention and is not intended to be limiting.

It is intended that the scope of the invention shall be limited only tothe extent required by the appended claims. Rather, the detaileddescription of the drawings, and the drawings themselves, disclose atleast one preferred embodiment of the invention, and may disclosealternative embodiments of the invention.

All elements claimed in any particular claim are essential to theinvention claimed in that particular claim. Consequently, replacement ofone or more claimed elements constitutes reconstruction and not repair.Additionally, benefits, other advantages, and solutions to problems havebeen described with regard to specific embodiments. The benefits,advantages, solutions to problems, and any element or elements that maycause any benefit, advantage, or solution to occur or become morepronounced, however, are not to be construed as critical, required, oressential features or elements of any or all of the claims.

Moreover, embodiments and limitations disclosed herein are not dedicatedto the public under the doctrine of dedication if the embodiments and/orlimitations: (1) are not expressly claimed in the claims; and (2) are orare potentially equivalents of express elements and/or limitations inthe claims under the doctrine of equivalents.

1.-16. (canceled)
 17. A method of automatically selecting one or moretransmission frequencies from five or more potential carrierfrequencies, the method comprising: scanning the five or more potentialcarrier frequencies to determine a first signal strength indication ofeach of the five or more potential carrier frequencies; storing thefirst signal strength indication of each of the five or more potentialcarrier frequencies in memory; rescanning the five or more potentialcarrier frequencies to determine a second signal strength indication ofeach of the five or more potential carrier frequencies; choosing a firsttransmission frequency from the five or more potential carrierfrequencies at least partially based on the first signal strengthindication and the second signal strength indication of each of the fiveor more potential carrier frequencies; and transmitting electricalsignals on the first transmission frequency, wherein: the one or moretransmission frequencies comprise the first transmission frequency. 18.The method of claim 17, wherein: rescanning the five or more potentialfrequencies occurs automatically a predetermined time period afterscanning the five or more potential carrier frequencies.
 19. The methodof claim 17, further comprising: after choosing the first transmissionfrequency, storing the second signal strength indication of each of thefive or more potential carrier frequencies in the memory; rescanning thefive or more potential carrier frequencies to determine a third signalstrength indication of each of the five or more potential carrierfrequencies; choosing a second transmission frequency from the five ormore potential carrier frequencies at least partially based on the firstsignal strength indication, the second signal strength indication, andthe third signal strength indication of each of the five or morepotential carrier frequencies; and transmitting electrical signals onthe second transmission frequency.
 20. The method of claim 17, wherein:storing the first signal strength indication of each of the five or morepotential carrier frequencies comprises: determining a first signalstrength score for each of the five or more potential carrierfrequencies using the first signal strength indication of each of thefive or more potential carrier frequencies and a previous signalstrength score of each of the five or more potential carrierfrequencies; and choosing the first transmission frequency comprises:determining a second signal strength score for each of the five or morepotential carrier frequencies using the second signal strengthindication of each of the five or more potential carrier frequencies andthe first signal strength score of each of the five or more potentialcarrier frequencies; and choosing the first transmission frequency fromthe five or more potential carrier frequencies at least partially basedon the second signal strength score for each of the five or morepotential carrier frequencies.
 21. The method of claim 17, furthercomprising: tuning a transmitter to the first transmission frequency.22. The method of claim 17, further comprising: providing the firsttransmission frequency to a user by visually displaying the firsttransmission frequency to the user.
 23. The method of claim 17, wherein:providing the first transmission frequency comprises: transmitting thefirst transmission frequency to a radio frequency receiver; andautomatically tuning the radio frequency receiver to the firsttransmission frequency.
 24. The method of claim 17, further comprising:encoding identifying information regarding the first transmissionfrequency into an alternative frequency portion of radio broadcast datasystem data of a second carrier frequency.
 25. The method of claim 24,further comprising: using the first electrical device to transmit theidentifying information.
 26. The method of claim 25, wherein: using thefirst electrical device to transmit the identifying informationcomprises: using the first electrical device to transmit the identifyinginformation over the alternative frequency portion of the radiobroadcast data system data of the second carrier frequency.
 27. Themethod of claim 17, further comprising: using the first electricaldevice to transmit identifying information for the first transmissionfrequency over a subcarrier frequency of a second carrier frequency. 28.The method of claim 27, further comprising: receiving the identifyinginformation using a receiver; automatically tuning the receiver to thefirst transmission frequency after receiving the identifyinginformation; and using the receiver to receive the electrical signalsbroadcast over the first transmission frequency.
 29. The method of claim27, further comprising: using the first electrical device to transmitthe identifying information before transmitting the electrical signalson the first transmission frequency.
 30. The method of claim 17, furthercomprising: before choosing the first transmission frequency, removing apotential carrier frequency from the five or more potential carrierfrequencies based on characteristics of one or more carrier frequenciesadjacent to the potential carrier frequency of the five or morepotential carrier frequencies.
 31. A method of automatically selectingtwo or more transmission frequencies from five or more potential carrierfrequencies, the method comprising: scanning the five or more potentialcarrier frequencies to determine a first signal strength indication ofeach of the five or more potential carrier frequencies; determining afirst signal strength score for each of the five or more potentialcarrier frequencies using at least the first signal strength indicationof each of the five or more potential carrier frequencies and a previoussignal strength score of each of the five or more potential carrierfrequencies; storing the first signal strength score of each of the fiveor more potential carrier frequencies in memory; selecting a firsttransmission frequency from the five or more potential carrierfrequencies at least partially based on the first signal strengthindication of each of the five or more potential carrier frequencies;broadcasting electrical signals over the first transmission frequency;rescanning the five or more potential carrier frequencies to determine asecond signal strength indication of each of the five or more potentialcarrier frequencies; determining a second signal strength score for eachof the five or more potential carrier frequencies using the secondsignal strength indication of each of the five or more potential carrierfrequencies and the first signal strength score of each of the five ormore potential carrier frequencies; storing the second signal strengthscore of each of the five or more potential carrier frequencies in thememory; selecting a second transmission frequency from the five or morepotential carrier frequencies at least partially based on the secondsignal strength score for each of the five or more potential carrierfrequencies; and broadcasting the electrical signals over the secondtransmission frequency, wherein: the two or more transmissionfrequencies comprise the first transmission frequency and the secondtransmission frequency.
 32. The method of claim 31, further comprising:determining one or more default signal strength scores for each of thefive or more potential carrier frequencies, wherein: the previous signalstrength score of each of the five or more potential carrier frequenciescomprises the one or more default signal strength scores for each of thefive or more potential carrier frequencies.
 33. The method of claim 31,further comprising: rescanning the five or more potential carrierfrequencies to determine a third signal strength indication of each ofthe five or more potential carrier frequencies; determining a thirdsignal strength score for each of the five or more potential carrierfrequencies using the third signal strength indication of each of thefive or more potential carrier frequencies and the second signalstrength score of each of the five or more potential carrierfrequencies; storing the third signal strength score of each of the fiveor more potential carrier frequencies in the memory; selecting a thirdtransmission frequency from the five or more potential carrierfrequencies at least partially based on the third signal strength scorefor each of the five or more potential carrier frequencies; andbroadcasting the electrical signals over the third transmissionfrequency, wherein: the two or more transmission frequencies furthercomprise the third transmission frequency.
 34. The method of claim 31,further comprising: providing the first transmission frequency to a userby visually displaying the first transmission frequency to the user. 35.The method of claim 31, further comprising: encoding identifyinginformation regarding the first transmission frequency into analternative frequency portion of radio broadcast data system data of asecond carrier frequency; and using the first electrical device totransmit the identifying information regarding the first transmissionfrequency over a subcarrier frequency of the second carrier frequency.36. A method of automatically selecting two or more transmissionfrequencies from five or more potential carrier frequencies, the methodcomprising: measuring a first signal strength indication for the five ormore potential carrier frequencies at a first time; determining a firstsignal strength score for each of the five or more potential carrierfrequencies at least partially based upon the first signal strengthindication for the five or more potential carrier frequencies at thefirst time; storing information related to the first signal strengthindication for each of the five or more potential carrier frequencies;selecting a first transmission frequency from the five or more potentialcarrier frequencies using at least in part the first signal strengthindication for the five or more potential carrier frequencies at thefirst time; broadcasting electrical signals over the first transmissionfrequency of the two or more transmission frequencies; measuring asecond signal strength indication for each of the five or more potentialcarrier frequencies at a second time; determining a second signalstrength score for each of the five or more potential carrierfrequencies at least partially based upon the second signal strengthindication of each of the five or more potential carrier frequencies atthe second time and the first signal strength score for the five or morepotential carrier frequencies; storing information related to the secondsignal strength indication for each of the five or more potentialcarrier frequencies; selecting a second transmission frequency from thefive or more potential carrier frequencies using at least in part thesecond signal strength indication for the five or more potential carrierfrequencies at the second time; and broadcasting the electrical signalsover the second transmission frequency of the two or more transmissionfrequencies, wherein: the first time is different from the second time.